| EPSRC Reference: |
GR/T05783/01 |
| Title: |
Dynamics of soft-glassy materials |
| Principal Investigator: |
Bartlett, Professor P |
| Other Investigators: |
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| Department: |
Chemistry |
| Organisation: |
University of Bristol |
| Scheme: |
Standard Research (Pre-FEC) |
| Starts: |
01 July 2004 |
Ends: |
30 September 2007 |
Value (£): |
301,509
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| EPSRC Research Topic Classifications: |
| Complex fluids & soft solids |
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Summary on Grant Application Form |
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Understanding glassy materials is an outstanding challenge in statistical physics. Recent theoretical arguments suggest that the intermolecular motion within glasses should be characterised by not one but two temperatures. After a temperature quench short length and fast timescales equilibrate extremely rapidly to the thermal or laboratory temperature To while large-scale slower motions remain stubbornly stuck far from equilibrium. Recent glass theories predict, rather surprisingly, that these slow glassy dynamics relax according to a second or an effective temperature, which exceeds To. This two-temperature picture has been widely invoked in the theoretical literature, but to date there has been no convincing experimental confirmation of its validity. Our aim is to test the concept of an effective glass temperature using single-particle optical tweezer techniques. We plan to determine simultaneously the microscopic diffusivity and the mobility of a single colloidal particle embedded within a glass. At equilibrium, the strength of thermal fluctuations are proportional to the dissipative response with the proportionality constant defining the temperature. In a glass, theory predicts the ratio between the measurable fluctuations and dissipative response may be used to define an effective temperature. If the two-temperature picture holds, then our measurements will reveal two distinct linear regimes with an effective temperature which depends on the scale of observation. Measurements will be made for a range of different particle sizes to identify if the theoretical concept of an effective temperature is clearly-defined.
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Key Findings |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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Potential use in non-academic contexts |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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Impacts |
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| Description |
This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk |
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| Date Materialised |
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Sectors submitted by the Researcher |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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| Project URL: |
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| Further Information: |
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| Organisation Website: |
http://www.bris.ac.uk |